This is an open-label, non-randomized, Phase II study with a lead-in safety cohort. Through the safety lead-in portion of this trial we will define the optimal dose of cabazitaxel when given in combination with lapatinib for patients with HER2-positive MBC and CNS metastases. The Phase II portion will further assess intracranial response rate in patients with HER2-positive MBC and CNS metastases. Toxicity and progression free survival (PFS) will be obtained and evaluated. The trial will be conducted at multiple study sites by SCRI Development Innovations.